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Objectives The aim of this RCT was to compare the accuracy of implant placement between static and dynamic computer‐assisted implant surgery (CAIS) systems in single tooth space. Materials and methods A total of 60 patients in need of a single implant were randomly assigned to two CAIS groups (Static n = 30, Dynamic n = 30) and implants were placed by one surgeon. Preoperative CBCT was transferred to implant planning software to plan the optimal implant position. Implants were placed using either stereolithographic guide template (Static CAIS) or implant navigation system (Dynamic CAIS). Postoperative CBCT was imported to implant planning software, and deviation analysis with the planned position was performed. Primary outcomes were the deviation measurements at implant platform, apex, and angle of placement. Secondary outcome was the distribution of the implant deviation into each 3D direction. Results The mean deviation at implant platform and implant apex in the static CAIS group was 0.97 ± 0.44 mm and 1.28 ± 0.46 mm, while that in the dynamic CAIS group was 1.05 ± 0.44 mm and 1.29 ± 0.50 mm, respectively. The angular deviation in static and dynamic CAIS group was 2.84 ± 1.71 degrees and 3.06 ± 1.37 degrees. None of the above differences between the two groups reached statistical significance. The deviation of implants toward the mesial direction in dynamic CAIS group was significantly higher than that of the static CAIS (p = 0.032). Conclusions Implant placement accuracy in single tooth space using dynamic CAIS appear to be the same to that of static CAIS. (Thai Clinical Trials Registry TCTR20180826001).

The optimal three-dimensional (3D) implant position is a critically important factor for the long-term success of implant therapy, as it can ensure the proper design of the prosthesis. Optimal positioning of the implant can allow for favourable prosthetic outcomes, such as function, aesthetics, occlusion and implant loading patterns. Moreover, correct implant position is essential for ensuring a prosthesis design compatible with long-term maintenance and access for adequate oral hygiene (Assche et al., 2012; Cooper, 2015; Tahmaseb, Wismeijer, Coucke, & Derksen, 2014).Key factors for long-term implant success include proper planning of the ideal implant position and precise transfer of the planned position to the surgical site. The outcome of conventional planning has been achieved with the use of a radiographic stent with a radiopaque marker, produced from duplicating the wax-up of the ideal prostheses on study models. The radiographic stent is then worn by the patient during a pre-operative cone beam computed tomography (CBCT) scan, thereby allowing transposition of the ideal prosthesis shape to the alveolar ridge and indicating the ideal prosthetic position for the implant. The radiographic stent can be thereafter Abstract Aim: This randomized controlled clinical trial (RCT) aimed to compare the accuracy of implant positions between static computer-assisted implant surgery (CAIS) and freehand implant surgery in a single edentulous space. Materials and methods:Sites with single edentulous spaces and neighbouring natural teeth were randomized into static CAIS or freehand implant surgery groups. In both groups, digital implant planning was performed using data from cone beam computed tomography (CBCT) and surface scans. In the static CAIS group, a surgical guide was produced and used for fully guided implant surgery, while in the freehand group, the implants were placed in a freehand manner. Postoperative CBCT was used for nine measurements representing the deviations in angles, implant shoulders and apexes between planned and actual implant positions.Results: Fifty-two patients received 60 single implants. The median (IQR) deviations in angles, shoulders and apexes were 2.8 (2.6)°, 0.9 (0.8) mm and 1.2 (0.9) mm, respectively, in the static CAIS group, and 7.0 (7.0)°, 1.3 (0.7) mm and 2.2 (1.2) mm, respectively, in the freehand group. Statistically significant differences were found in 6 out of nine measured parameters using Mann-Whitney U test (p < 0.05). Conclusion:Static CAIS provided more accuracy in implant positions than freehand placement in a single edentulous space. K E Y W O R D Saccuracy of implant position, dental implant, freehand implant surgery, static computerassisted implant surgery

Human gingival fibroblasts (HGFs), a predominant cell type in tooth-supporting structure, are presently recognized for their active role in the innate immune response. They produce a variety of inflammatory cytokines in response to microbial components such as LPS from the key periodontal pathogen, Porphyromonas gingivalis. In this study, we demonstrated that HGFs expressed mRNA of TLRs 1, 2, 3, 4, 5, 6, and 9, but not TLRs 7, 8, and 10. Stimulation of HGFs with highly purified TLR2 ligand (P. gingivalis LPS), TLR3 ligand (poly(I:C)), TLR4 ligand (Escherichia coli LPS), and TLR5 ligand (Salmonella typhimurium flagellin) led to expression of IL-8 and IDO. A potent TLR 9 ligand, CpG oligodeoxynucleotide 2006 had no effect, although HGFs showed a detectable TLR9 mRNA expression. No significant enhancement on IL-8 or IDO expression was observed when HGFs were stimulated with various combinations of TLR ligands. Surprisingly, the TLR9 ligand CpG oligodeoxynucleotide 2006 was able to specifically inhibit poly(I:C)-induced IL-8 and IDO expression. TNF-α enhanced TLR ligand-induced IL-8 production in HGFs, whereas IFN-γ enhanced TLR ligand-induced IDO expression. HGF production of IDO in response to P. gingivalis LPS, IFN-γ, or the two in combination inhibited T cell proliferation in MLRs. The observed T cell inhibition could be reversed by addition of either 1-methyl-dl-tryptophan or l-tryptophan. Our results suggest an important role of HGFs not only in orchestrating the innate immune response, but also in dampening potentially harmful hyperactive inflammation in periodontal tissue.

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